Hello everyone. New here on Plantedtank. Just got into this planted aquarium thing serious, and after many years in the hobby, I've finally decided to do an aquascaped aquarium. I've always admired the beauty of the iwagumi aquariums and am going to shoot for something along those lines. In the interest of reducing viewable clutter, I'm going with a mini refugium type setup and will try to stuff everything in there(filters, heater, co2 diffuser, etc, it's going to get tricky). I have the two sponge filters in my big aquarium getting cultured and will put those in the refugium once I have everything pretty much ready to cycle. All I have is my cell camera so the pics are not the best. Posted on AAPE too, but I'm gathering all resources I can. Here we go!

Here are the "parts"
6.6gal bookshelf aquarium from petco.
Fugeray 24 & 10" lights from finnex
Nutrafin CO2 kit from Hagen
HOB refugium/breeder from finnex
shiruba mini water pump
Eco complete substrate
2x sponge filters
seiryu stones
parts from some old sponge filters, check valves, thermometers, etc.
This is what the tank comes with. Flourescent hood, HOB power filter, top and bottom frame.
This is what I am going to actually use. Ditched the top frame(rimless!), light and filter.
As with most of my tanks, the back got painted with black hammerite. I like the black look with the holes in it that hammerite makes. It's hard to capture in a picture, but it gives it a subtle texture and still black when viewed from the front and full of water.
Got impatient and started sawing on the old donor sponge filter before I got a picture. But here it is midway through dissection.
Here we have the HOB refugium/breeder/soon to be frankenfilter before modifications.
I wasn't going to even try to explain how this part goes together, so a picture will have to do. Green parts are from the old sponge filter, grey parts are from the new refugium. Threw on a fluval edge sponge over the strainer as I'm eventually going to keep CRS in here. One point which I would like input on is the green part with the air inlet on it. I am going to have the co2 enter here, sort of like "filter intake" diffusion. The magnet on the motor is downward, so there shouldn't be much issue with air getting in there and overheating. My main concern is will this be enough exposure time in the water for the co2?
Here is the aquarium fabbed up.
As with the AAPE forum, let me know what you think or if anyone sees any glaring pitfalls, I'm a noob......I'm going to start adding ingredients tomorrow probably, woohoo! Glad to be here, thank you for looking and any constructive feedback!